Catalytic Enantioselective Reductive Eschenmoser–Claisen Rearrangements
Nicolai Cramer reports on DAP-catalyzed, highly enantioselective Eschenmoser–Claisen rearrangements.
Professor Nicolai Cramer from the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland explained that the Claisen rearrangement, with a history of more than 100 years of synthetic usage since its discovery, is a stereoselective sigmatropic rearrangement that it has been utilized extensively in constructing carbon stereocenters. Especially, it is possible to control the relative stereochemistry of contiguous stereocenters containing all-carbon quaternary carbons. Achieving catalytic enantioselective Claisen rearrangements is still a challenge for catalysis. Professor Cramer explained that, unlike the reported catalytic modes involving weak interactions, the designed covalent substrate–catalyst bond encountered during the 1,3,2-diazaphospholene (DAP) catalysis provides an attractive pathway to overcome these challenges.
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